Relles, Nathan. A user interface for online assistance. 1981. In Proceedings of 5th
International Conference on Software Engineering. New York: Institute for Electrical
and Electronics Engineers. 400-408.

Roemer, J. M. and Champanis, A. 1982. Learning performance and attitudes as a function
of the reading grade level of a computer-presented tutorial. In Proceedings of Human
Factors in Computer Systems Conference. Gaithersburg, MD: Institute for Computer
Sciences and Technology, National Bureau of Standards. 239-244.